Tesla may experience some fluctuations in production rates, Mr. Musk said, but “people should have zero concerns” about the company’s ability to increase production of the new offering, the Model 3.

Mr. Musk’s comments came on a conference call after Tesla announced its second-quarter earnings. Despite the company experiencing a widening loss as it continued to invest in factories to accommodate the Model 3, investors found plenty to like in its prospects. Tesla shares were up more than 7 percent in extended trading.

Tesla said it lost $401.4 million in the quarter that ended June 30, compared with a loss of $293.2 million in the same period in 2016.

At the same time, the company reported overall growth in its operations, which include its automotive business and its solar-panel division.

Tesla’s reported a net loss of $336 million, or $2.04 per share, compared to a loss of $293 million, or $2.09 a share, a year ago.

Excluding stock based compensation, Tesla lost $1.33 a share, which was narrower than expected, according to a consensus estimate from Thomson Reuters.

Revenue climbed to $2.79 billion from $1.27 billion in the year-ago period, and outpacing Wall Street’s estimates of $2.51 billion.

Shares surged roughly 8 percent in after market trading. Since the start of the year, Tesla shares have gained 52 percent, as investors anticipate the launch of its first car for a more mainstream consumer.

Heading into the earnings report, analysts expressed concerns about whether Tesla would ramp up production of its Model 3, a more affordable electric car with a base cost of $35,000, quick enough. In the past, Tesla has struggled with production issues.

The results came after Tesla’s big event on Friday to launch the mass-market Model 3.

In the earnings letter, Tesla said it averaged over 1,800 net Model 3 reservations daily and was confident it could produce just over 1,500 vehicles in the third quarter. Deliveries to non-Tesla employees would start in the fourth quarter, Tesla said.

Tesla had said it planned to produce 500,000 vehicles annually by 2018 and would ramp up costs to meet that goal. The company burned through $1.16 billion in cash in the second quarter, up from $144 million a year before.

Analysts at Morgan Stanley and Baird were focused on vehicle demand, especially since the Model 3 could cannibalize Tesla’s older cars.

“Although too early to draw strong conclusions, we are seeing an even further increase in net Model S orders since the July 28th event,” Tesla said.

Chris Roush is the Walter E. Hussman Sr. Distinguished Professor in business journalism at UNC-Chapel Hill. He is a former business journalist for Bloomberg News, Businessweek, The Atlanta Journal-Constitution, The Tampa Tribune and the Sarasota Herald-Tribune. He is the author of the leading business reporting textbook "Show me the Money: Writing Business and Economics Stories for Mass Communication" and "Thinking Things Over," a biography of former Wall Street Journal editor Vermont Royster.